PETERSBURG, Va. (AP) - Sen. Tim Kaine is defending his committee vote for limited strikes on Syria. But he says President Barack Obama should not order the attacks if Congress refuses to authorize them.

The Democratic junior senator said Thursday that Syrian President Bashar Assad's regime must be punished for its suspected use of chemical weapons Aug. 21 in a rebel-held suburb of Damascus.

But he told reporters after addressing a Virginia State University ROTC class that it's important for America's military to undertake its mission knowing it has the U.S. government's undivided backing.

If Congress rejects Obama's appeal to authorize limited military strikes, Kaine says the president should honor that decision.

Kaine voted for a strike Wednesday in a Senate Foreign Relations subcommittee. A full Senate vote is expected next week.